Horsepower meter



MAY l1, 1943 c. D. wALDRoN Erm. 2,318,645'

HoRsEPowER METERv INVENTORS CLO YD D. WA LDRoN POBEPT'E SELDEN A'ITORN ZMay 11, 1943 c. D. WALDRON Erm. 2,318,645

HORSEPOWER METER Filed June 25, 1940 2 Sheets-Sheet 2 INVENToRs CLOYD D.WALDRON BY ROBERT/: SELDGN ArroRNl-:Yrhw

Patented May l1, v1943 FUN71TED;v l.S"l"A'.l`E`S PATENT OFFICE UTY-. 1*52 o. 2,318,645 v p, Y ffnoasnrowarm'rnn I ooyfil n. Waldron. NewportNews. and Robert F.

wwfseldemllamptomva. apbuoatioo'rono 2s, 194o,"ser1a1 No. 342,310

t i 'Y comme. (crass-zo) o `the actfof March 3, 1883, as

aprirao, 1928;.--370 o. G. 157) l y 'l-he present 1 invention-' relatesto meters, i and Yithas ;a,particulaauf relationitoL-meters forindieating the lhorsepower; revolutions per minute, andbrake mean.eective vpressure:developed by an aeroll'utical internal combustionengine.-

- One :of` the-'objectsf'of "this inventionlisv the provision yofa-hors'epowermeterof the character described twhich will-correlate` thetorque and revolutions., per minuterof thefengin'e-in such manner asv toindicate thezsam'e -in -terms .of the horsepowerdevelopedf 1 Y ,Anotherobjectzof; this invention-is the -provision of a horsepower meter havingadial rotatable in one directionwith amotion'lwhich is :proportionaltothe logarithm of the torquebe- .-ing transmitted,.- therdial havinggraduations ,thereon `in terms ofpoundsper. square inchfbrake meaneffective pressure :that iare'indicated by a stationary pointer; and acooperating hand 2.whichrotates in adirection oppositetofthat of the.dial with aJmotion which is proportional V'toi'.he logarithm of therotativespeedof Isome tionsl-thereon fin; terms 'of horsepower that fareindicated bytheposition-'of the speed hand;

,p A further object of this 'inventionis'the *pro- .vision of-ahorsepower meter, the mechanism-of which. `is adiustable to accommodateit; to :erigines withwdifferent propeller reduction` o gear ratiostoaccommodate `itto engines with different-displacements: and whichincludes means for; adapting the meter. to indicate accurately thehorsepower developed vbythe engine when the meter issubjected tovaryinglbarometric pressures of ,dierentaltitudea 1 Y with tneseend otherobjects in vienes wu as other advantages that may be incident to the useof they improvements, the' inventiony -fcori'sists in theparts andcombinations thereof hereinafter set forth and claimed, with theunderstand- :into practical use, without limiting the improvements intheir useful application to the particularconstruction, which, for ythepurpose of ex- Fig. 1 is a front elevational view of a horsepower meterconstructed in accordance with the v invention, with the nameplateremoved;

through the meter taken on line 2-2 of Fig. 1; and

Fig. 2 is a Vertical longitudinal sectional view Figs. 3, 4, 5 and 6 arevertical transverse secvtional views taken on lines 3 3, 4 4, 5--5 and6-6, respectively, of Fig. 2.

, Referring to the drawings, a horsepower meter embodying theinventionis shown as comprising va cylindrical casing IU closed at its rearA endby a wall Il and having a glassfront I2. The interior of the casing isprovidedwith spaced front and rear brackets I6 and I1, which aresecuredto lugs I8 rand I9 formed on the interior circumferential surfaceof the casing. A bracket Z0-is; mountedv on the front bracket I6 inspaced relation thereto by means of posts 2l, and to- .gether -with thebracket I6 forms the support [for a, tubular shaft 22 journalled inbearings 23 mounted therein.

horsepower developed by the engine and has a smaller dial 21 graduatedto indicate engine V brake mean effective pressure, adjustably securedthereto by means of screws 28 *passing through arcuate slots 29 formedin the smaller dial. The dials 24 and 21 movetogether when `the shaft 22is rotated and cooperate with a fixed dial 30 secured to the casing I0,as indicated at 3|'.` This dial is provided with a central opening 32-to'provide access to the screwsI 25 and 28 and'is also provided with aWindow 33 through which the graduations on the smaller dial 2l A maybeobserved with relation to apointer 34 ing` that the several necessaryelements constil. -tuting the samemay be variedinproportion andyarrangement without departing from thevnature and scopeoftheinvetion',"as defined inthe `appe'n'dedclalms.'

j ,In order to 1a.keftl'1e;rv invention moreclearly understood, there'are' shown in the` accompanyng'drawn'gs, means for carrying theinvention on th'exed dial 30, and through which mark 95 horsepower dial24 may be observed with relationv to the pointer 36. Extending throughthe tubular shaft 22 and mounted for rotation therein is a shaft 35having a pointer 36 secured 2 I to its forward endfor cooperation withthe graduations on the dials 24 and 3|).`

The tubular shaft 22 is rotated in 'order to rvo tate the horsepower andbrake mean effective measuring device of the engine.

The free or movable end of the/Bourdon tube 31, or other pressuresensitive element, is pivotally connected by a link 4| with one leg 42lof abell crank lever 48, the other leg 44 of which is xed to anoncircular segmental gear 45, which is mounted on a pivot shaft 45journalled in the bracket I5 and the bracket 28,1Tigs. 2 and 4. 'I'he 1segmental gear 45 meshes with and drives a noncircular segmental pinion41 which is fixed tothe tubular shaft 22 between the bearings 23.` Thelink u is formed with a slot is for pivotal and slidable engagementwitha pivot 49 that is rigidly attached to'Bourdonl tube 31. f Thus, whenthe Bourdon tube'expands orcontracts, with changes in the oil pressureof the torque measuringdevice, the link 4| will swing the bell cranklever 43 and noncircular gear 45 about the shaft 45 so Ias to transmitrotary motion to the `shaft 22` and dials 24 and 21. The arc of travelof the noncircular gear 45 may be adjusted to accommodate the instrumentto different types of torque measuring devices, by lengthening orshortening the effective lever arm of the leg 44 of the bell crankllever 43. 'I'his may be accomplished, as shown in Fig. 4, by providing aslot 55 in the leg 44 for slidable engagemer'it with the pivot shaft 45and a screw 5| threaded into the noncircular gear 45. The parts may beheld in their zero positions by means of a coiled hair spring 52 havingone end securedv to the bracket 28 andtheother end to the tubular shaft22.

The inner shaft is rotated in order to rotate the pointer 35 relative tothe fixed R. P. M. dial 35, by means of a centrifugal orother speedresponsive device, conventionally indicated in its Y entirety at 53,located in the rear of the casing.

This device comprises a tubular shaft 54 havingl a stud shaft fixed inits lower end which is iournalled in a bearing 55 mounted in a boss 51formed on the casing I8. A plug nut 58 is threaded into the boss 51 toprovide access to the bearing 55 so as to permit of the easy insertionand removal of this bearing. The upper end of the v upper end thereof.The lower end of the plunger 5| engages aball 52 which in turn engages aslide 53 having a groove 54 formed therein intermediate its ends.k Acollar 55 is flxed to the upper end of the tubular shaft 54 and isconnected by links 55 'y and centrifugally operable weights 51 with acollar 58 slidably mounted on the lower end of the tubular shaft 54.This collar is provided with a pin 59 which'extends through a slot 10 inthe tubular shaft for engagement with the groove 54 in the slide 53. Acoil spring 1| encircles the tubular shaft 54 between the collars 55 and58 and tends to urge them apart. Thus, it will be apparent that whenthe: device is rotated the weights 51 in moving outwardly will elevatethe lower collar 58 and slide it upwardly along the tubular shaft 54.This will cause the pin 59 to raise the slide 53 while rotating and inturn raise the non-rotating plunger 5|. 'I'he rotation of the device 53is effected through the medium of a gear 12 which meshes with' fa pinion13 on the i stud shaft 55 and which' is fixed to a shaft 14 journalledin a bearing 15 mounted in a nipple 15 formed on the casing I0. Theshaft 14 is connected in any suitable manner with the engine so as torotate in response to the speed thereof in the manner of a tachometer.

`The upper end of the non-rotating plunger 5| has a slot and pinconnection 11 with one end of a lever` 18 which is pivotally mounted onan ear 19 provided on the bracket |1. The other end of the lever 18extends over and engages an arm 85 fixed to a noncircular segmental gear8| which-is fixed to a shaft 82 journalled at its ends in the bracket l1and a bracket 83 mounted on the bracket |1v in spacedrelation thereto by-posts 84. 'I'he noncircular gear 8| meshes with a noncircular segmentalpinion 85 which is fixed to a shaft 85 also journalledin the bracket |1and the bracket 83. The forwardend ofthe shaft 85 carries an L-,shapedarm 81 which engages an arm 88 fixed to the inner end of the pointershaft 35. Thus, when the plunger 5| is raised, as previously described,the lever 18 will swing the noncircular gear 8| downwardly (in Fig. 6)and rotate the pinion.85 and rshaft 85.lv This will swing the arms 81and 88 so as to rotate the pointer shaft an amount proportional'to afunction of the speed of rotation of the engine. The pointer shaft 35 isurged toward its zero position by acoiled hair spring 89, .one end ofwhich is iixed to theshaft 35 and the other'end fixed to the bracket I5.

The object of the connection 8188 between .the shafts 85 and 35 is notonly to permit of slight misaligmnent of these shaftsinassembly withoutcausing thel pointer-shaft to bind, but also to permit the arms to beoffset angularly relative to one another when the. parts occupy theirzero positions.l `'Ihis prevents the meter from functioning at lowengine speeds. A nameplate 90 is fixed to a bracket arm- 9| carried bythe .casing |0 and covers the access openings in the dials 24 and 21.The arm 9|'a1soforms aforward support for the pointer shaft 35..

4A ASylplion bellows device or aneroid capsule v 92 may be connectedbetween the end of 'the Bourdon tube 31 and the link 4| so as tocompensate for variations in atmospheric pressures at differentaltitudes in cases in which the torque measuring device gives anabsolute pressure instead of a gauge pressure that is proportional to`torque. (Present devices give gauge pressure.) 4

The noncircular gears 45 and 41 are so designed that the approximatelinear motion of theBourdon tube 31 is convertedintoa logarithmic.rotaryl j motion of, the noncircular segmental"pinio'1 1f";4?|.1y Also,the noncircular gears 8| and -85'are sol'fdesigned that the approximatelineal-motion of the gear 8| changes to exactly a logarithmic rotationof the gear 85 in the range of R. P. M. in which horsepower is to beindicated. At low R. P. M at which it is not desired to indicatehorsepower the rotation of gear 85 does not have to be logarithmic withR. P. M., but can be any desired mo tion. This increases the smallestradial dimensions of gear 85, and also compresses the R. P. M. scale inthe range below that at which horsepower is desired.

Instead of noncircular segmental gears 45, 41, 8|, and 85 it is possiblein some instances to use The dial 24 is held against a stop 93 duringlow values of torque, and allowed -to 'make approximately one-halfrevolution in the range of torque above a specified value. This willrequire one row of horsepower values plotted logarithmically around thecircumference of the dial. Having the dial turn only one-halfrevolution, covering the lower half of the dial, and eliminating thelower range of horsepower values eliminate having two rows of horsepowervalues around'the dial, thus preventing the confusion of deciding whichrow of horsepower values to read.

The dial 21 adjustably mounted on the dial 24 can be calibrated in termsof propeller reduction gear ratio, or in numbers that can be referred toin a chart, prepared by the instrument manufacturer to cover all enginemodels for which the L power range of the instrument is suitable.

The adjustment for propeller reduction gear ratio that is made betweendial 24 and shaft 22 can be made by removing dial stop 93 and With shaft22 in some specified position set some specled value of horsepowerondial 24 at the edge 94 of dial 30. A chart can show what value ofhorsepower must be set at 94 to correspond to any desired propellerreduction gear ratio.

The adjustment between dials 24 and 21 can be made by line 95 on dial 24that shows under the enlargement 96 of window 33. Setting the propervalue of B. M. E. P. on dial 21 at mark 95 adjusts the B. M. E. P, scalefor any desired engine displacement.

On the stationary dial 30 that covers part of dial 24 is an R. P. M.scale composed of values of R. P. M. that are indicated by thetachometer pointer 36. These values of R. P. M. are laid outlogarithmically in the range of R. P. M. i-n which it is desired toindicate horsepower, and are laid out linearly or otherwise in the rangeof R. P. M. below that at which horsepower is desired.

Laying out R. P. M. and horsepower scales Assume a meter to be laid outfor an engine that develops 1,500 horsepower at 2,700 R. P. M. Maximumtorque will be 2,915 pound-feet.

Assume arbitrarily that the tachometer is to indicate engine speeds of400 to 3,500 R. P. M.

The steps to be'followed in -laying out the- R. P. M. and horsepowerscales are: First, lay out 400 to 3,500 R. P. M. on any desired part ofthe circumference of the stationary R. P. M. scale, the circumferentialdistance to each value of R. P. M. being proportional to the logarithmof each value of R. P. M. The mock-up meter shows 400 to 3,500 R. P. M.laid out on about seven-eighths of the circumference of the R. P. M.scale.

Gears 8 I and 85 must be so designed that the tachometer hand motionfollows this R. P. M.

scale.

Second, lay out the values of horsepower on the torque dial, the angulardistance for any given number of horsepower on the dial being the samevlas the angular distance for this same number of R. P. M. on the R. P.M. scale. For example, take the attached mock-up meter and turn the dialuntil 1,500 horsepower is at 1,500 R. P. M. It will be seen'that 1,400,1,300, 1,200, and 1,100 horsepower are at 1,400, v1,300, 1,200, and1,100 R. P. M. respectively. Thus, any desired horse- 'power scale canbe laid out from the R. P. M. fscale.

Gears as and 41 must be designed so that the dial rotates as though thevalues of horsepower were values of torque, 1,500 horsepower corre--sponding to 2,915 pound-feet of torque, and 1,000 horsepowercorresponding to v that the torque dial rotates from the position atwhich 360 horsepower on the dial is at 2,700 R. P. M. on the R. P. M.scale, to .the position at which 1,500 horsepower is at 2,700 R. P. M.,orfrom values of torque of.

pound-feet to 2,915 pound-feet.

It will be understood that the above description and accompanyingdrawings comprehend only the general and preferred embodiment of theinvention and that various changes in construction, proportion andarrangement of the parts may be made within the scope of the appendedclaims without sacrificing any of the advantages of the invention.

The invention described herein may be manufactured and/or used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

What is claimed is:

1. A horsepower meter comprising a rotatable dial having graduationsthereon indicating horsepower; non-circular intermeshing gears forrotating said dial; means responsive to the torque of the engine forrotating said gears, the curvature of said gears being such asto rotatesaid dial with a motion proportional to the logarithm of the torquebeing transmitted; a pointer cooperating with the graduations on saiddial; noncircular intermeshing gears for rotating said pointer in adirection opposite to that of said dial; means responsive to the speedof the engine for rotating said last mentioned gears, the curvature ofsaid last mentioned gears being such as to rotate said pointer with amotion proportional to the logarithm of the rotative speed of theengine, means for adjusting the degree of angular travel of saidrotatableA dial in accordance with the torque developed by the engine,and a lost motion connection between said speedrespensive means and saidpointer for delaying the movement of the latter during low enginespeeds.

2. A horsepower meter comprising a rotatable dial having graduationsthereon indicating horsepower; non-circular intermeshing gears forrotating said dial; means responsive to the torque of the engine forrotating said gears, the curvadial with a motion proportional to thelogarithm oi' the torque being. transmitted; a pointer cooperating withthe graduations on said dial; noncircular intermeshing gears forrotating said pointer in a direction opposite to that of said dial;means responsive to the speed of the engine for rotating said lastmentioned gears, the

curvature of said last mentioned gears being such as to rotate saidpointer with a motion proportional to the logarithm of the rotativespeed of the engine, and means for adjusting the degree of ture of saidgears being such as to rotate said angular travel of said rotatable dialin accordy ance with the torque developed by the engine,l

